NoSpamId type to include nospam + checksum + public key.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/Crypto/Tox.hs b/src/Crypto/Tox.hs
index 9a365daa..a43e3379 100644
--- a/src/Crypto/Tox.hs
+++ b/src/Crypto/Tox.hs
@@ -55,6 +55,7 @@ module Crypto.Tox
     , encryptSymmetric
     , encodeSecret
     , decodeSecret
+    , xorsum
     ) where
 
 import Control.Arrow
@@ -588,3 +589,13 @@ decodeSecret k64 = do
         CryptoPassed x -> Just x
         _              -> Nothing
 
+xorsum :: ByteArrayAccess ba => ba -> Word16
+xorsum bs = unsafeDupablePerformIO $ BA.withByteArray bs $ \ptr16 -> do
+    let (wcnt,r) = BA.length bs `divMod` 2
+        loop cnt !ac = do
+            ac' <- xor ac <$> peekElemOff ptr16 cnt
+            case cnt of 0 -> return ac'
+                        _ -> loop (cnt - 1) ac'
+    loop (wcnt - 1) $ case r of
+        0 -> 0
+        _ -> 256 * fromIntegral (BA.index bs (BA.length bs - 1))